DataSyncLog Runbook without specify SyncGroup

In sql-server-samples/samples/features/sql-data-sync/DataSyncLogPowerShellRunbook.ps1 when I don't specify a SyncGroup and it tries to run the following line in testing environment.

$SyncGroupName = Get-AzureRmSqlSyncGroup -ResourceGroupName $ResourceGroup -ServerName $Server -DatabaseName $Database | select -ExpandProperty SyncGroupName

I run into the below exception. I'm not a PS expert, but this is defined I believe. https://docs.microsoft.com/en-us/powershell/module/azurerm.sql/get-azurermsqlsyncgroup?view=azurermps-4.4.0

Get-AzureRmSqlSyncGroup : The term 'Get-AzureRmSqlSyncGroup' is not recognized as the name of a cmdlet, function, 
script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is 
correct and try again.
At line:165 char:38
+                     $SyncGroupName = Get-AzureRmSqlSyncGroup -Resourc ...
+                                      ~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (Get-AzureRmSqlSyncGroup:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

Start with sql-server-samples/samples/features/sql-data-sync/DataSyncLogPowerShellRunbook.ps1 around line 165, then review the linked Get-AzureRmSqlSyncGroup documentation. Run the runbook in the reported testing scenario without specifying a SyncGroup and investigate the missing-command exception. Done means that scenario no longer fails at the SyncGroup lookup.